Internal combustion engines, for example, diesel engines, gasoline engines, or natural gas engines employ turbochargers to deliver compressed air for combustion in the engine. A turbocharger compresses air flowing into the engine, helping to force more air into combustion chambers of the engine. The increased supply of air allows for increased fuel combustion in the combustion chambers of the engine, resulting in increased power output from the engine.
A typical turbocharger includes a shaft, a turbine wheel connected to one end of the shaft, a compressor wheel connected to the other end of the shaft, and bearings to support the shaft. Separate housings connected to each other enclose the compressor wheel, the turbine wheel, and the bearings. Exhaust from the engine expands over the turbine wheel and rotates the turbine wheel. The turbine wheel in turn rotates the compressor wheel via the shaft. The compressor wheel receives cool air from the ambient and forces compressed air into combustion chambers of the engine.
Natural inherent material limitations, flaws within the compressor wheel, wear and tear of the compressor stage components, excessive speeds, or debris in the intake air may cause a compressor wheel to fail. To prevent ejection of debris or oil in the event of a compressor wheel failure, turbochargers typically rely on massive housings surrounding the impeller to absorb the tremendous amount of energy released during the failure. The massive housings, however, tend to increase the volume, weight, and cost of the turbocharger. Additionally, although the housings may contain the debris and oil, damage imparted to the housings by the failed compressor wheel components may require expensive and time consuming repairs to the housings, which may place the turbocharger out of service for an extended time period.
U.S. Pat. No. 6,638,007 B2 of Bartholomä et al. that issued on Oct. 28, 2003 (“the '007 patent”) discloses a compressor casing that attempts to retain failed compressor components within the casing. In particular, the '007 patent discloses that the compressor casing has an outer spiral casing fastened using a rigid fixing arrangement to a bearing casing of a turbomachine. The '007 patent further discloses that the spiral casing includes an inner cylinder to which a casing insert piece is attached using a flexible attachment arrangement, forming a hollow space between the casing insert piece and the spiral casing. The '007 patent discloses that the flexible attachment arrangement is less secure against fracture as compared to the rigid fixing arrangement. The '007 patent also discloses that the flexible fixing arrangement of the casing insert piece can absorb considerably more kinetic energy than a rigid fixing arrangement. The '007 patent explains that in an emergency, the casing insert piece can move away from the compressor impeller in the axial direction and that the kinetic energy of the compressor impeller pieces can be largely absorbed by conversion into deformation energy and the heat resulting from it. The '007 patent further explains that the residual kinetic energy of the fragments can be absorbed by the casings.
Although the '007 patent discloses a compressor casing designed to contain pieces of a failed impeller, the disclosed casing may still not be optimal. For example, in the event of impeller failure, the casing insert may detach from the spiral casing and move axially outwards, allowing pieces of the impeller to still impact and damage the bearing casing. This may require expensive and time consuming repairs to the bearing casing before the turbomachine can return to service. Damage to the bearing casing may also allow oil to leak from within the turbomachine.
The compressor assembly of the present disclosure solves one or more of the problems set forth above and/or other problems of the prior art.